This study of alkali-burned rabbit corneas was designed to understand more about the cellular and tissue regulatory responses that control the elaboration of the enzyme collagenase, one of the chief factors responsible for corneal ulceration and melting. The present project is to 1) document and localize the elaboration of collagenase by corneal tissues, 2) examine the interaction of blood monocytes and their products with corneal cells in stimulating enzyme production, 3) examine the interaction of regenerated and normal corneal epithelium and stroma in enzyme production, and 4) learn more about the regulation of collagenase production and collagen synthesis by corticosteroid and progestational hormones.